In current rolls with slide bearings, a roll shell is supported on a roll shaft by means of hydrostatic slide bearing elements acting radially (also axially) on the roll shell and being loaded by means of a hydraulic pressure fluid. Generally, at least two of the slide bearing elements, so-called loading elements, act on the roll shell in directions opposite to each other in the direction of a plane co-directional with a primary loading. At least two of the slide bearing elements, so-called lateral bearing elements, act on the roll shell in a direction lateral to a plane co-directional with the primary loading. This configuration is described in patent publication F1 98320. There, when an external force, for example a force resulting from a nip load, is applied to a roll shell and, thus, to loading elements, a regulator, for example a slide-type valve, mechanically in connection with the loading elements, is used for adjusting the pressure prevailing in the cavity of a slide bearing element closer to a higher loading to surpass the pressure of a loading element acting in the opposite direction so as to offset the external forces. A similar arrangement is implemented for lateral bearing elements, as well. Each slide bearing element is supplied with a constant pressure by way of regulators.
It is also prior known to support a roll shell in its middle section for the adjustment of a nip load by means of several, at least two counter zones. For such arrangement, reference can be made to patent publication FI 98554. There, the inner surface of a roll shell is subjected to the action of counter zone elements/chambers set e.g. in two rows, which produce a sum force working in a nip plane in a direction substantially opposite to the force produced by a loading element.
However, the above-described arrangement is solely intended to prevent a displacement or stroke of the roll shell relative to the shaft. Heavy bearing loads become a problem in this arrangement. Subjected to such loads, the roll shell tends to turn elliptical as a result of the action of loading elements, even though the roll shell would otherwise remain essentially stationary. If the ellipticity development is not stopped, the stresses in a shell may become so severe that the shell could break as a result of fatigue.